1. Field of the Invention
This invention relates in general to electrical connectors for coaxial cable and more particularly to an angled connector for receiving a bent electrical terminal attached to, or for attachment to, a coaxial cable.
2. Discussion of Related Art
In transmitting a signal through a central conductor of a coaxial cable, it is generally preferred to have noise-free transmission. More specifically, it is desired to minimize radio frequency (RF) interference and noise levels. However, routing of coaxial cables often requires the cables to be arranged perpendicularly or at other angles to the connection ports or printed circuit boards they serve. In general, the cables lack the flexibility needed to make sharp bends at the locations of these ports and boards. Therefore, rather than bending the cables, terminals for connecting the cables to the connection ports and printed circuit boards are typically bent to provide the needed turn. For example, U.S. Pat. No. 6,126,482 discloses a right-angle terminal for crimping to a cable conductor and making a right angle turn to a mating contact end for receipt by a cooperating connection port.
It is common practice to utilize a soldered joint for terminating cable center conductors to the bent terminal, or to provide a right angle connection, as illustrated for instance by U.S. Pat. No. 4,799,900. Soldered joints are typically more expensive and time consuming than the simpler crimp connections, and usually must be done after the wire end and terminal are placed in the connector. However, both soldered and crimped joints reduce the RF performance of the connection. Significant geometry variations in the signal path caused by the bend area of the terminal instigate further interference and noise.
The cable end, terminal connection and terminal contact are usually enclosed by an angled connector to protect the terminal and shield the connection, such as disclosed in U.S. Pat. No. 5,362,255. In this patent, a right-angle terminal-to-wire engagement is surrounded by a right-angle, hinged connector. Since the cable termination is a soldered joint and the connector does not grip an inner portion of the wire, the connector has to be securely attached to a conventional braiding layer of the cable to prevent the cable from being pulled out of the connector. This requires a separate tool to spread out the cable braiding prior to the soldering process, adding a step to the assembly procedure. After the hinged connector components are closed around the terminal connection and stripped end of the cable, a sleeve slides over the spread braiding to deform it into a tubular shape surrounding the engaged parts of the components. The sleeve is then crimped in position. This holds the hinged components closed around the joint and mechanically secures the braiding, and therefore the cable, to the connector.
In the above-described devices, and in other standard coaxial cable connectors, internal cavities or chambers are formed around the terminal and cable conductor joint and around the bend in the terminal. These chambers often provide sharp corners, other uneven surfaces and alternately narrowing and widening cavities that interfere with the signal passing through the connector and considerably reduce the RF performance of the connection. It seems there has not been a serious attempt to minimize signal loss in this environment in a straightforward manner.
Accordingly, it is an object of this invention to provide an angled electrical connector with a tuned internal chamber or cavity for minimizing radio frequency interference.
Another object of this invention is to form the tuned cavity by components of the connector interacting as the connector is assembled around a coaxial cable termination or bent terminal for a printed circuit board (PCB).
A still further object of this invention is to furnish a connector having these important characteristics but still utilizing low cost manufacturing and assembly methods.
In carrying out this invention in the illustrative embodiment thereof, the conductor core or central wire of a coaxial cable is crimped to a terminal. The terminal has a right-angle bend providing a change of direction of the cable from a crimp section to a contact section for engagement with a cooperating connection port. A right-angle connector has a main body and a cover. The cover can be opened or separated from the main body to allow insertion of the terminal into the main body. The main body has a curved passageway or channel with an opening that receives the crimp section, bend and contact sections of the terminal. The main body has a partially tubular portion that receives the end of the coaxial cable. The contact section of the terminal is surrounded by an outer contact barrel or socket extending from an output end of the main body. The socket has a dielectric lining.
The cover has a flat portion and a partially tubular portion. The flat portion has a shaped projection that fits into the channel opening when the cover is moved to a closed position with the flat portion seated on the main body. The projection closes the opening and completes assembly of a tuned chamber or cavity by providing a surface that seamlessly merges and matches with the curved passageway. The cavity is L-shaped with a circular cross-section and no sharp corners, obstacles or recesses. The cover is secured in the closed position by a ferrule slid over the partially tubular portion of the cover and the partially tubular portion of the main body, which are now engaged to provide a tube enclosing the end of the cable.
A solid dielectric member may be used to fill the cavity rather than simply using air as the dielectric. The dielectric member would include hinged parts as needed for fitting around the bent terminal and allowing ease of assembly. In a variation of the invention, the tuned cavity is formed in PCB connector. A dielectric member is closed around a bent contact or terminal and then inserted into a connector housing prior to engagement of the terminal and housing with a PCB.
Because of the tuned cavity, the geometry variations caused by the crimp and bend sections of the terminal are virtually eliminated or reduced to a degree that enables the RF connector to function at higher performance levels than were previously achievable. Cost reduction occurs because the open connector and tuned cavity allow use and insertion of the relatively inexpensive crimp connection and common bent center contact. The design, therefore, provides a relatively low cost right-angle cable connector and PCB connector that utilize simple manufacturing and assembling techniques while increasing the RF performance at the same time. Straight action assembly and molding for flexibility in the assembly process and ease of manufacturing, respectively, and the use of basic crimping technology, add up to a very cost-effective design. The assembly can be either manual or automated since the design lends itself to these simple assembly methods.